If you've spent more than five minutes online, you've probably seen an ad that promises "find out who's searching for you." It sounds like a scam, but is it possible? Can someone find out if you've been looking at their Facebook or LinkedIn profile? Can you tell if someone's unfriended you? And can you see what searches have been performed with your name?
First the warning: there are scams aplenty promising to show you who is "stalking" your Facebook page. I put in a call to Facebook and spoke with their technical folks, the truth is, NO ONE can see who's been on your Facebook page. There are no features buried in the Facebook settings with that data. There are no apps that can unearth that info. Facebook says it is one of the most common scam come-ons on the site. Don't fall for it; you cannot see who's looking at your profile (and no one can see if you've been looking at theirs).
BUT there are apps and tools to see who's unfriended you. Facebook tries to squelch these apps, but I found a couple — one that you download to your computer called UnFriend Finder and one for Android called Friends Checker. Sign in, and they store a list of your friends. Then every time you check back, it tells you who's no longer on the list. UnFriend Finder also reminds you of friend requests you've made that haven't been answered. For Twitter, Qwitter does the same thing, telling you who's unfollowed you each week.